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LASIK / PRK /
LASEK
LASIK (laser assisted in-situ keratomileusis) is the most common
laser vision correction procedure performed today
and can correct a wide range of conditions, including nearsightedness,
farsightedness, and astigmatism. Using a highly accurate, cold beam
excimer laser, the LASIK surgeon reshapes the cornea (the clear window on
the front of the eye) to focus light rays directly on the retina.
During the LASIK surgery, a thin corneal flap is created using an
instrument called a microkeratome. The corneal flap is gently folded back,
and the excimer laser uses pulses of invisible
ultraviolet light to gently reshape the internal tissue of the cornea.
Each pulse of the laser removes only a minute amount of corneal tissue -
about 1/500th of the thickness of a human hair. Depending on which is
applicable, the laser is either guided by the
WavePrint™ map created specifically for your eye or by the surgeon's
skilled adjustment of the laser. The surgeon has full control of the laser
and can turn it off at any time.
Once the cornea is reshaped, the corneal flap is replaced in its original
position where it adheres quickly and seals itself without the need for
stitches. The surgery only takes about five minutes per eye, and there is
very little discomfort, either during the surgery or after. Typically, by
the day after surgery, LASIK patients see
well enough to drive and return to work.
PRK and
LASEK (Advanced Surface Ablation)
PRK (photo-refractive keratectomy) and LASEK (laser epithelial
keratomileusis) are both advanced surface ablation procedures used to
correct vision by using the excimer laser to shape the surface of the
cornea, rather than the interior. PRK was the first FDA-approved procedure
changing the curvature of the cornea with the excimer
laser. Safety and clinical data on the first PRK surgeries date back
to 1990.
PRK and LASEK use the same excimer laser as LASIK and the same
Wavefront mapping, but the procedures are
performed on the surface rather than inside the cornea. With PRK, the
epithelium (top skin layer) of the cornea is actually removed; with LASEK,
the epithelium is moved aside and then replaced after surgery. In each
case, the laser is then used on the surface of the corneal tissue only.
To assist the healing process after PRK and LASEK, a clear bandage contact
lens is placed over the cornea during the 3-5 days needed for the
epithelium to re-grow. Additionally, patients are normally placed on a
regimen of steroid eye drops for a three to six month period, requiring
monitoring by their doctor on a weekly or monthly basis. Like LASIK, PRK
and LASEK only take about five minutes per eye, and the surgery itself is
painless. There is typically more discomfort during the healing process
after advanced surface ablation procedures, and it takes a bit more time
for the patient to see clearly, but in the end, outcomes for LASIK, PRK,
and LASEK are the same.
There are some medical conditions that may make either PRK or LASEK more
suitable than LASIK. LASEK, for example, is used mostly for people with
thin corneas since LASIK requires more corneal tissue to be successful.
PRK is often preferred for patients who may be susceptible to dry eyes
since dry eyes are more often a complication of LASIK.
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